9c92ab6191
Based on 1 normalized pattern(s): this software is licensed under the terms of the gnu general public license version 2 as published by the free software foundation and may be copied distributed and modified under those terms this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 285 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141900.642774971@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
141 lines
3.6 KiB
C
141 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Toggles a GPIO pin to restart a device
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*
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* Copyright (C) 2014 Google, Inc.
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*
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* Based on the gpio-poweroff driver.
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*/
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#include <linux/reboot.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/gpio/consumer.h>
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#include <linux/of_platform.h>
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#include <linux/module.h>
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struct gpio_restart {
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struct gpio_desc *reset_gpio;
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struct notifier_block restart_handler;
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u32 active_delay_ms;
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u32 inactive_delay_ms;
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u32 wait_delay_ms;
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};
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static int gpio_restart_notify(struct notifier_block *this,
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unsigned long mode, void *cmd)
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{
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struct gpio_restart *gpio_restart =
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container_of(this, struct gpio_restart, restart_handler);
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/* drive it active, also inactive->active edge */
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gpiod_direction_output(gpio_restart->reset_gpio, 1);
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mdelay(gpio_restart->active_delay_ms);
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/* drive inactive, also active->inactive edge */
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gpiod_set_value(gpio_restart->reset_gpio, 0);
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mdelay(gpio_restart->inactive_delay_ms);
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/* drive it active, also inactive->active edge */
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gpiod_set_value(gpio_restart->reset_gpio, 1);
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/* give it some time */
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mdelay(gpio_restart->wait_delay_ms);
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WARN_ON(1);
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return NOTIFY_DONE;
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}
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static int gpio_restart_probe(struct platform_device *pdev)
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{
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struct gpio_restart *gpio_restart;
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bool open_source = false;
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u32 property;
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int ret;
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gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart),
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GFP_KERNEL);
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if (!gpio_restart)
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return -ENOMEM;
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open_source = of_property_read_bool(pdev->dev.of_node, "open-source");
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gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL,
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open_source ? GPIOD_IN : GPIOD_OUT_LOW);
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if (IS_ERR(gpio_restart->reset_gpio)) {
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dev_err(&pdev->dev, "Could net get reset GPIO\n");
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return PTR_ERR(gpio_restart->reset_gpio);
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}
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gpio_restart->restart_handler.notifier_call = gpio_restart_notify;
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gpio_restart->restart_handler.priority = 129;
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gpio_restart->active_delay_ms = 100;
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gpio_restart->inactive_delay_ms = 100;
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gpio_restart->wait_delay_ms = 3000;
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ret = of_property_read_u32(pdev->dev.of_node, "priority", &property);
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if (!ret) {
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if (property > 255)
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dev_err(&pdev->dev, "Invalid priority property: %u\n",
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property);
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else
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gpio_restart->restart_handler.priority = property;
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}
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of_property_read_u32(pdev->dev.of_node, "active-delay",
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&gpio_restart->active_delay_ms);
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of_property_read_u32(pdev->dev.of_node, "inactive-delay",
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&gpio_restart->inactive_delay_ms);
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of_property_read_u32(pdev->dev.of_node, "wait-delay",
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&gpio_restart->wait_delay_ms);
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platform_set_drvdata(pdev, gpio_restart);
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ret = register_restart_handler(&gpio_restart->restart_handler);
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if (ret) {
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dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n",
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__func__, ret);
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return -ENODEV;
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}
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return 0;
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}
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static int gpio_restart_remove(struct platform_device *pdev)
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{
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struct gpio_restart *gpio_restart = platform_get_drvdata(pdev);
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int ret;
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ret = unregister_restart_handler(&gpio_restart->restart_handler);
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if (ret) {
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dev_err(&pdev->dev,
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"%s: cannot unregister restart handler, %d\n",
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__func__, ret);
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return -ENODEV;
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}
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return 0;
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}
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static const struct of_device_id of_gpio_restart_match[] = {
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{ .compatible = "gpio-restart", },
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{},
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};
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static struct platform_driver gpio_restart_driver = {
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.probe = gpio_restart_probe,
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.remove = gpio_restart_remove,
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.driver = {
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.name = "restart-gpio",
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.of_match_table = of_gpio_restart_match,
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},
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};
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module_platform_driver(gpio_restart_driver);
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MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
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MODULE_DESCRIPTION("GPIO restart driver");
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MODULE_LICENSE("GPL");
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